环氧树脂绝缘高频电热联合老化中局部放电特性分析
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摘要
电力电子变压器长期运行于高频正弦电压下,其绝缘更易受到局部放电作用影响从而导致老化失效。为此以环氧树脂材料为研究对象,模拟电力电子变压器的运行条件,在30 k Hz、4 kV的正弦电压和温度120℃下开展了电热联合加速老化试验,研究了不同老化阶段下绝缘的高频局部放电特征。实验结果表明:高频正弦电压下残余电荷扩散少,放电连续,放电相位范围超过90°,局部放电频繁冲击绝缘材料;随着老化时间的增长,高相位上的最大放电幅值由0.02 V增加到0.03 V,局部放电相位分布谱图(PRPD)中第2簇"三角"特征更为明显,统计参量Sk能较准确地反应绝缘的老化状态;同时,随着绝缘缺陷表面有效起始电子产生概率的变化,放电量和放电次数总体呈上升趋势,局部放电的相位范围向两端扩展。
During a power electronic transformer's(PET's) service period, the key factor that determines the insulation life of transformer is partial discharge. In order to simulate PET operation, we conducted electrical-thermal aging tests with epoxy resin insulation under 130 ℃ and 4 kV、30 k Hz of sinusoidal alternating voltage. Partial discharges at different aging stages are recorded and studied. The experiment results show that, high-frequency supply voltage will reduce the space charges decaying rate to arise the repeated PD pulses, broaden the distribution of PD phase beyond 90° and bring drastic reaction in the insulation. With insulation's aging, there is an increase of the maximum discharge quantity between high phases from 0.02 V to 0.03 V and a more obvious triangle-like form among second cluster of phase-resolved partial discharge(PRPD) patterns. The skewness at different aging time can be considered as a reference of insulation's aging course. Also, the probability of effective initial electrons for PD on the surface of defects varies with aging time. The discharge quantity and discharge number turn larger and the distribution of PD phase widens toward both ends.
During a power electronic transformer's(PET's) service period, the key factor that determines the insulation life of transformer is partial discharge. In order to simulate PET operation, we conducted electrical-thermal aging tests with epoxy resin insulation under 130 ℃ and 4 kV、30 k Hz of sinusoidal alternating voltage. Partial discharges at different aging stages are recorded and studied. The experiment results show that, high-frequency supply voltage will reduce the space charges decaying rate to arise the repeated PD pulses, broaden the distribution of PD phase beyond 90° and bring drastic reaction in the insulation. With insulation's aging, there is an increase of the maximum discharge quantity between high phases from 0.02 V to 0.03 V and a more obvious triangle-like form among second cluster of phase-resolved partial discharge(PRPD) patterns. The skewness at different aging time can be considered as a reference of insulation's aging course. Also, the probability of effective initial electrons for PD on the surface of defects varies with aging time. The discharge quantity and discharge number turn larger and the distribution of PD phase widens toward both ends.
引文
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[10]Naoki H,Hitoshi O.Partial discharge characteristics of inverter-fed motor coil samples under AC and surge voltage conditions[J].IEEE Electrical Insulation Magazine,2005,21(1):5-10.
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[12]王鹏,高波,吴广宁,等.连续方波电压下变频电机绝缘局部放电特性[J].高电压技术,2013,39(6):1522-1526.WANG Peng,GAO Bo,WU Guangning,et al.Partial discharge characteristics of inverter-fed motor insulation at repetitive square wave voltages[J].High Voltage Engineering,2013,39(6):1522-1526.
[13]张婷婷,周力行,向洋.绝缘热老化局部放电信号频域分析的实验研究[J].绝缘材料,2008,41(3):49-51.ZHANG Tingting,ZHOU Lixing,XIANG Yang.Analysis on frequency domain of partial discharge signal during the thermal aging[J].Insulating Materials,2008,41(3):49-51.
[14]唐炬,谢颜斌,朱伟,等.用于复小波变换的EWC阈值法抑制周期性窄带干扰[J].电力系统自动化,2005,29(7):43-47.TANG Ju,XIE Yanbin,ZHU Wei,et al.Suppression of narrowband interference with EWC threshold method for complex wavelet transform[J].Automation of Electric Power Systems,2005,29(7):43-47.
[15]张晓虹,张亮,乐波,等.基于局部放电的矩特征分析大电机主绝缘的老化[J].中国电机工程学报,2002,22(5):95-99.ZHANG Xiaohong,ZHANG Liang,YUE Bo,et al.Analysis on aging condition of stator winding insulation of generator based on the moment characteristics of partial discharge[J].Proceedings of the CSEE,2002,22(5):95-99.
[16]Yue B,Chen X L,Cheng Y H,et al.Aging assessment of large generator insulation based on PD measurements[J].Progress in Natural Science,2005,15(11):1035-1043.
[17]Tadeusz L.Measurement of solid dielectric surface temperature increment arising from partial discharge activity[C]∥IEEE Electrical Insulation.Anaheim,USA:IEEE,2000:324-327.
[18]Lutz N.A generalized approach to partial discharge modeling[J].IEEE Transaction on Dielectrics and Electrical Insulation,1995,2(4):510-528.
[19]Gutfleisch F,Niemeyer L.Measurement and simulation of PD in epoxy voids[J].IEEE Transactions on Dielectrics and Electrical Insulation,1995,2(5):729-743.
[20]Temmen K.Evaluation of surface changes in flat cavities due to ageing by means of phase-angle resolved partial discharge measurement[J].Journal of Physics D:Applied Physics,2000,33(6):603-608.
[21]尹毅,肖登明,屠德民,等.TSC/TSL联合谱在绝缘聚合物电老化研究中的应用[J].中国电机工程学报,2002,22(3):1-5.YIN Yi,XIAO Dengming,TU Demin,et al.Application of TSC/TSL-UNITED-SPECTRA in investigation of electrical aging in insulating polymer[J].Proceedings of the CSEE,2002,22(3):1-5.
[22]Hudon C,Barinikas R,Wertheimer M R.Spark-to-glow discharge transition due to increased surface conductivity on epoxy resin specimens[J].IEEE Transactions on Electrical Insulation,1993,28(1):1-8.
[23]刁常晋,程养春,邓春,等.阶梯升压试验和恒定电压试验中油纸绝缘局部放电发展规律的对比[J].高电压技术,2013,39(2):365-373.DIAO Changjin,CHENG Yangchun,DENG Chun,et al.Contrast of the developing regularity of partial discharge of oil-paper insulation using step-stress test and constant-stress test[J].High Voltage Engineering,2013,39(2):365-373.
[2]Filchev T,Cook D,Wheeler P,et al.High power,high voltage,high frequency transformer/rectifier for HV industrial applications[C]∥IEEE Power Electronics and Motion Control Conference.Poznań,Poland:IEEE,2008:1326-1331.
[3]Lothar H.An actively cooled high power,high frequency transformer with high insulation capability[C]∥IEEE Applied Power Electronics Conference and Exposition.Dallas,USA:IEEE,2002:352-357.
[4]Leung C,Dutta S,Baek S,et al.Design considerations of high voltage and high frequency three phase transformer for solid state transformer application[C]∥Energy Conversion Congress and Exposition(ECCE).Atlanta,USA:[s.n.],2010:1551-1558.
[5]Saha Tapan K.Review of modem diagnostic techniques for assessing insulation condition in aged transformers[J].IEEE Transactions on Dielectrics and Electrical Insulation,2003,10(5):903-917.
[6]廖瑞金,严家明,杨丽君,等.油浸绝缘纸损伤与局部放电相位分布模式演化的关系[J].电工技术学报,2011,26(6):199-206.LIAO Ruijin,YAN Jiaming,YANG Lijun,et al.Relationship between damage of oil-immersed paper and evolution of phase-resolved partial discharge patterns[J].Transactions of China Electrotechnical Society,2011,26(6):199-206.
[7]吴锴,秦锴,孙常浩,等.电负性气体对局部放电特性的影响[J].高电压技术,2010,36(6):1372-1378.WU Kai,QIN Kai,SUN Changhao,et al.Effect of electronegative gas on partial discharge characteristics[J].High Voltage Engineering,2010,36(6):1372-1378.
[8]周凯,吴广宁,吴建东,等.基于局部放电统计参量的脉冲电压下绝缘老化分析[J].电工技术学报,2008,23(4):6-12.ZHOU Kai,WU Guangning,WU Jiandong,et al.Analysis of aging properties for insulation based on statistical parameters of partial discharge under pulse voltage[J].Transactions of China Electrotechnical Society,2008,23(4):6-12.
[9]Wu K,Okamoto T,Suzuoki Y.Transition of partial discharge behavior with aging under square-wave AC voltage[C]∥IEEE Properties and applications of Dielectric Materials.Bali,Indonesia:IEEE,2006:36-39.
[10]Naoki H,Hitoshi O.Partial discharge characteristics of inverter-fed motor coil samples under AC and surge voltage conditions[J].IEEE Electrical Insulation Magazine,2005,21(1):5-10.
[11]Forssen C,Edin H.Partial discharges in a cavity at variable applied frequency,part 1:measurements[J].IEEE Transaction on Dielectrics and Electrical Insulation,2008,15(6):1061-1069.
[12]王鹏,高波,吴广宁,等.连续方波电压下变频电机绝缘局部放电特性[J].高电压技术,2013,39(6):1522-1526.WANG Peng,GAO Bo,WU Guangning,et al.Partial discharge characteristics of inverter-fed motor insulation at repetitive square wave voltages[J].High Voltage Engineering,2013,39(6):1522-1526.
[13]张婷婷,周力行,向洋.绝缘热老化局部放电信号频域分析的实验研究[J].绝缘材料,2008,41(3):49-51.ZHANG Tingting,ZHOU Lixing,XIANG Yang.Analysis on frequency domain of partial discharge signal during the thermal aging[J].Insulating Materials,2008,41(3):49-51.
[14]唐炬,谢颜斌,朱伟,等.用于复小波变换的EWC阈值法抑制周期性窄带干扰[J].电力系统自动化,2005,29(7):43-47.TANG Ju,XIE Yanbin,ZHU Wei,et al.Suppression of narrowband interference with EWC threshold method for complex wavelet transform[J].Automation of Electric Power Systems,2005,29(7):43-47.
[15]张晓虹,张亮,乐波,等.基于局部放电的矩特征分析大电机主绝缘的老化[J].中国电机工程学报,2002,22(5):95-99.ZHANG Xiaohong,ZHANG Liang,YUE Bo,et al.Analysis on aging condition of stator winding insulation of generator based on the moment characteristics of partial discharge[J].Proceedings of the CSEE,2002,22(5):95-99.
[16]Yue B,Chen X L,Cheng Y H,et al.Aging assessment of large generator insulation based on PD measurements[J].Progress in Natural Science,2005,15(11):1035-1043.
[17]Tadeusz L.Measurement of solid dielectric surface temperature increment arising from partial discharge activity[C]∥IEEE Electrical Insulation.Anaheim,USA:IEEE,2000:324-327.
[18]Lutz N.A generalized approach to partial discharge modeling[J].IEEE Transaction on Dielectrics and Electrical Insulation,1995,2(4):510-528.
[19]Gutfleisch F,Niemeyer L.Measurement and simulation of PD in epoxy voids[J].IEEE Transactions on Dielectrics and Electrical Insulation,1995,2(5):729-743.
[20]Temmen K.Evaluation of surface changes in flat cavities due to ageing by means of phase-angle resolved partial discharge measurement[J].Journal of Physics D:Applied Physics,2000,33(6):603-608.
[21]尹毅,肖登明,屠德民,等.TSC/TSL联合谱在绝缘聚合物电老化研究中的应用[J].中国电机工程学报,2002,22(3):1-5.YIN Yi,XIAO Dengming,TU Demin,et al.Application of TSC/TSL-UNITED-SPECTRA in investigation of electrical aging in insulating polymer[J].Proceedings of the CSEE,2002,22(3):1-5.
[22]Hudon C,Barinikas R,Wertheimer M R.Spark-to-glow discharge transition due to increased surface conductivity on epoxy resin specimens[J].IEEE Transactions on Electrical Insulation,1993,28(1):1-8.
[23]刁常晋,程养春,邓春,等.阶梯升压试验和恒定电压试验中油纸绝缘局部放电发展规律的对比[J].高电压技术,2013,39(2):365-373.DIAO Changjin,CHENG Yangchun,DENG Chun,et al.Contrast of the developing regularity of partial discharge of oil-paper insulation using step-stress test and constant-stress test[J].High Voltage Engineering,2013,39(2):365-373.